• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.428-434
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• 2001

After miniplate fixation of mandibular angle fractures, fracture line stability during functional loading was evaluated. Using panoramic radiographs, 15 mandibular angle fracture patients who were treated by open reduction and one miniplate fixation along the external oblique ridge, were evaluated at postoperative 1, 4 and 8 weeks. At each time, 2 radiographs were taken: one taken during maximum biting of hardened silicone sheet on the affected side molar area and the other on the non-affected side. The distraction gap of inferior border of mandible at each time and each side was measured and these data were analysed statistically with clinical findings. The differences of inferior border distraction gap during hardened silicone sheet biting on the affected side molar area and on the non-affected side molar area at 4 week radiographs were smaller than those of 1 week's except one case. At 8 week's radiographs, the fracture lines were so stabilized that it was almost impossible to find the gap differences except one case and there were increased radiopacity along the entire fracture lines. Clinically, bony union was confirmed in all cases during plate removal performed at postoperative 6 month. By statistical analysis(paired t-test), the inferior border distraction gap during biting of hardened silicone sheet on the affected side was significantly reduced during 1 and 4 week interval(p<0.01). The differences of inferior border distraction gap during biting on the affected side molar area and on the non-affected side molar area were also significantly reduced at 1 and 4 week interval(p<0.01). But the inferior border distraction(compression) gap during non-affected side biting was not significantly changed. From these findings, it could be concluded that fracture line stability during functional loading after one miniplate fixation of mandibular angle fractures stems mainly from reduction of inferior border distraction gap during affected side biting on time interval. According to these radiographic and clinical findings, the clinical superiority of one miniplate fixation technique in mandibular angle fracture treatment could be confirmed.

• Imaging Science in Dentistry
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• v.42 no.3
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• pp.139-146
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• 2012

Purpose: An individual surgical stent fabricated from computed tomography (CT) data, called a CT-guided stent, would be useful for accurate installation of implants. The purpose of the present study was to introduce a newly developed CT-guided stent with a simple design and evaluate the accuracy of the stent placement. Materials and Methods: A resin template was fabricated from a hog mandible and a specially designed plastic plate, with 4 metal balls inserted in it for radiographic recognition, was attached to the occlusal surface of the template. With the surgical stent applied, CT images were taken, and virtual implants were placed using software. The spatial positions of the virtually positioned implants were acquired and implant guiding holes were drilled into the surgical stent using a specially designed 5-axis drilling machine. The surgical stent was placed on the mandible and CT images were taken again. The discrepancy between the central axis of the drilled holes on the second CT images and the virtually installed implants on the first CT images was evaluated. Results: The deviation of the entry point and angulation of the central axis in the reference plane were $0.47{\pm}0.27$ mm, $0.57{\pm}0.23$ mm, and $0.64{\pm}0.16^{\circ}$, $0.57{\pm}0.15^{\circ}$, respectively. However, for the two different angulations in each group, the $20^{\circ}$ angulation showed a greater error in the deviation of the entry point than did the $10^{\circ}$ angulation. Conclusion: The CT-guided template proposed in this study was highly accurate. It could replace existing implant guide systems to reduce costs and effort.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.35.1-35.7
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• 2018

Background: After the resection at the mandibular site involving oral cancer, free vascularized fibular graft, a type of vascularized autograft, is often used for the mandibular reconstruction. Titanium mesh (T-mesh) and particulate cancellous bone and marrow (PCBM), however, a type of non-vascularized autograft, can also be used for the reconstruction. With the T-mesh applied even in the chin and angle areas, an aesthetic contour with adequate strength and stable fixation can be achieved, and the pores of the mesh will allow the rapid revascularization of the bone graft site. Especially, this technique does not require microvascular training; as such, the surgery time can be shortened. This advantage allows older patients to undergo the reconstructive surgery. Case presentation: Reported in this article are two cases of mandibular reconstruction using the ready-made type and custom-made type T-mesh, respectively, after mandibular resection. We had operated double blind peer-review process. A 79-year-old female patient visited the authors' clinic with gingival swelling and pain on the left mandibular region. After wide excision and segmental mandibulectomy, a pectoralis major myocutaneous flap was used to cover the intraoral defect. Fourteen months postoperatively, reconstruction using a ready-made type T-mesh (Striker-Leibinger, Freibrug, Germany) and iliac PCBM was done to repair the mandible left body defect. Another 62-year-old female patient visited the authors' clinic with pain on the right mandibular region. After wide excision and segmental mandibulectomy on the mandibular squamous cell carcinoma (SCC), reconstruction was done with a reconstruction plate and a right fibula free flap. Sixteen months postoperatively, reconstruction using a custom-made type T-mesh and iliac PCBM was done to repair the mandibular defect after the failure of the fibula free flap. The CAD-CAM T-mesh was made prior to the operation. Conclusions: In both cases, sufficient new-bone formation was observed in terms of volume and strength. In the CAD-CAM custom-made type T-mesh case, especially, it was much easier to fix screws onto the adjacent mandible, and after the removal of the mesh, the appearance of both patients improved, and the neo-mandibular body showed adequate bony volume for implant or prosthetic restoration.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.173-178
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• 1987

Osteogenic sarcoma is a malignant primary tumor of bone composed of a malignant connective tissue stroma with evidence of malignant osteoid, bone and/or cartilage formation. A 23year old man was admitted to dental department of Yeungnam University hospital with chief complaint of swelling and pain on alveolar ridge of lower right molar region. It was certain of osteogenic sarcoma through clinical and radiographic features and biopsy. Surgical resection of the lesion was performed by partial mandibulectomy and resin plate insertion. By follow up check of the patient, we made good result of functional reconstruction without any sign of recurrence of the lesion.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.238-249
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• 2005

The contemporary two-jaw surgical approach usually involves a Le Fort osteotomy of the maxilla and a ramal osteotomy of the mandible with 3-dimensional repositioning of the jaws as well as the occlusal planes. After making the surgical treatment plan. the surgical movements are duplicated in the model surgery. During this procedure, reference poings and lines are drawn on the base of the models over the dental arch and sawcuts are mads according to these marked osteotomy lines. This technique, however, has been found to be inexact. especially when the laws are moved in several dimensions simultaneously. To overcome this. different methods have been developed for an accurate repositioning of the jaws as planned. A new appliance. Surgical Jaw Relater, has been devised by th8 author for the simple 3-dimensional relocation of the upper and lower models, resulting in the easy construction of the splints such as centric relation splint, intermediate and final splint. This article describes an introduction and a clinical application of this appliance. Through the application of this system to the orthognathic cases including two-law surgery. it is proved that the row device is very clinically useful.

• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.67-75
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• 1995

The progress of periodontal disease and the wound healing process after treatment result in alveolar bone bone change. So, detection of it is very important in the diagnosis and the radiograph of periodontal disease. Various effects have been made to assess the subtle alveolar bone change and digital subtraction radiography (DSR) has been reported to be the best method in evaluating it qualitatively and quantitatively. The present study was performed to estimate the detectable alveolar bone change qualitatively with digital subtraction radiography. For the in vitro study, 10 intraoral standard radiographs were taken from porcine dry mandible which a rectangular cortical bone chip of 0.1mm to 1.0mm thickness with 0.1mm increment was attached on the buccal surface. The radiographs without and with bone plates were reviewed at the same time by 10 observers and requested to detect the presence of cortical bone plates. Digital Subtraction radiograph was reviewed subsequently by using the DSR system(digital converter-256 grey-levels,DT 2851,Data Translation Co., U.S.A;IBM 386 ; CCD camera, FOTOVIX, Tamrom Co., Japan). The detectable thickness of cortical bone plate was O.4mm on the intraoral radiograph and 0.2mm on the subtaction images. For the human study, radiographs were taken from patients by using intraoral film holding device and aluminum reference wedge before and 3 month after bone graft and 1 week after osteoplasty. The grey level change was estimated in the subtraction images and calculated to aluminum equivalent thickness. The grey level of the grafted site was higher that that of healthy controls. Average grey levels of change on healthy controls were O.48mm aluminum equivalent. However, the amount of changes in grafted sites were 1.87mm aluminum thickness equivalent and in the site of osteoplasty were -1.49mm aluminum thickness equivalent. In conclusion, digital subtraction radiography was more effective in detecting as subtle change of alveolar bone than intraoral standard radiography. With the aid of quantitative analysis of digital subtraction radiography, alveolar bone resorption of apposition can be estimated during diagnosis and treatment of periodontally diseased patients.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.107-120
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• 1987

The purpose of this study was three-fold: to reexamine whether periapical and central lesions can be detected on the radiograph when they are in the cancellous bone, to investigate regianal differences in radiograph visualization of the lesion, and to. compare the interpretation of radiagraphs by densitometric analysis with the visual interpretation af the same radiographs. Forty-nine apical lesions and eighty-two central lesions were made in 8 mandibles and radiographed serially while being enlarged and deepened. All radiagraphs were evaluated by three dental radiologists. Each lesion was scored of 3 to 0, based on the radiographic appearances. Special radiographs of 15 apical and central lesions were analysed by densitometer and the results were compared with the scores which were previously assigned by three examiners. From this study the following conclusians could be drawn; 1. Experimental lesions confined to cancellous bone were detected an the radiagraphs in 41.3% of the cases. 2. Visualization of periapical lesions in cancellous bone was more apparent than that of central lesions in cancellous bone. 3. Visualization of the periapical lesions confined to. cancellous bane was highest in molar teeth, and detection of the central lesions in alveolar portion was easier than those in lower portion of mandibular body area. 4. It was possible to detect the experimental lesions without cortical plate involvement in 78.6% of the all lesions. 5. Densitometric analysis of radiographs could reproducibly distinguish bone changes, especially of central lesions in cancellous bone.

• The Journal of Korean Academy of Prosthodontics
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• v.26 no.1
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• pp.63-84
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• 1988

Recently the instantaneous centre concept has been used to understand the biomechanics by which a tissue derangement causes a mechanical derangement in temporomandibular joint. In this study, four male subjects without temporomandibular joint disorder and malocclusion were selected for the determination of the instantaneous centre of rotation (I.C.R) in the mandibular movement. The habitual opening and closing paths were recorded on the sagittal plate by two spring pencils attached on the lower anterior teeth which was designed for this study, and the I.C.R. was calculated by the computer program of Rouleaux's method. Also the computer graphic opening and closing movements of mandible were obtained according to the determined I.C.R. The results obtained from this study were as follows. 1. The instantaneous centres of rotation were not positioned within the condyle in the mandibular opening and closing movement. 2. There was some similarity between the anatomical curvature of the articular emience and the movement pattern of condyle. 3. The opening path and the closing path of the most superior pl)int of the condyle stowed a slight difference. 4. At the early stage of the habitual opening movement, the condyle was moved downward. 5. The opening and closing mandibular movements were simulated by the instantaneous centre of rotation which was determined by the computer program of Rouleaux's method.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.4
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• pp.338-347
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• 2001

Purpose: This is to review the cases of posterior maxillary segmental osteotomies to regain the interarch spaces for dental implants in the posterior mandible. Materials & Methods: Seven patients who presented with alveolar extrusion of upper posterior molars underwent segmental osteotomies by single-stage Kufner's buccal approach under the intravenous sedation and local anesthesia. The posterior maxillary cento-alveolar segments were repositioned upward using pre-fabricated palato-occlusal resin splints and immobilized with osteosynthesis microplates and screws. Dental implants were installated simultaneously. The regained spaces, tooth vitality, periodontal healing, relapse, tenderness on function, and complications including maxillary sinus involvements were evaluated periodically for over one year after the surgeries. Results: The single-tage procedures were completed within 80 minutes without any surgical complications. The posterior maxillary segments were repositioned upward to regain the interarch spaces ranging from 2.5 to 5.5mm. All teeth involved in the procedures keep their vitalities. The repositioned segments were maintained showing neither evidence of periodontal break-down nor tenderness to function. One patient whose segments had not been immobilized by osteosynthesis plate resulted in 2mm down-ward relapse in post-operative 8 months. A case of postoperative nasal bleeding from the posterior-lateral wall resulted in oroantral fistula and chronic maxillary sinusitis later. Conclusion: The extruded dento-alveolar segments of the posterior maxilla were repositioned properly by Kufner's one-stage segmental osteotomies. One microplate can be of help to keep the position until the osseous healing enough to support the masticatory force.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.6 no.1
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• pp.15-18
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• 2010

Sturge-Weber syndrome is a rare nonhereditary developmental condition that is characterized by a hamartomatous vascular proliferation involving the tissue of brain and face. The clinical features are characterized by port wine nevus following one or more divisions of trigeminal nerve, ocular involvement and neurologic involvement such as epilepsy, mental retardation, and contralateral hemiplegia. Oral manifestations include unilateral blood vessel expansion of the oral mucosa, vascular hyperplasia of gingiva, pyogenic granuloma-like massive hemangiomatous proliferation of oral mucosa, macrodontia, ipsilateral macroglossia, blood vessel anomaly of maxilla or mandible and abnormal tooth eruption sequence. This case report is about 11-year-old Sturge-Weber syndrome patient presented port wine nevus on the face, venous malformation on soft plate and buccal mucosa. In this case we performed simple extraction of several deciduous teeth and periodic oral hygiene management. If a patient with Sturge-Weber syndrome has to undergo dental surgery in affected areas of the mouth, great care must be taken to prevent severe hemorrhage.